Memory system for an electric typewriter

ABSTRACT

A typewriter provided with a bail operatively positioned upon initiation of a first type action to block the drive of a subsequently initiated type action or shift action and hold it in memory until the first type action has been substantially completed. The bail is also operatively positioned upon initiation of a shift action to block the drive of a subsequently initiated type action and hold it in memory until the shift action has been substantially completed.

United States Patent Arthur R. Johnson Wethersfield, Conn.

Sept. 20, 1968 Mar. 9, 1971 Litton Business Systems, Inc. New York, N .Y.

[ 72] Inventor [21 Appl. No. [22] Filed [45] Patented [73] Assignee [54] MEMORY SYSTEM FOR AN ELECTRIC TYPEWRITER. 5 Claims, 8 Drawing Figs.

Reichle 197/74 3,045,799 7/1962 Seymour et a1. 197/107 3,077,971 2/1963 Palmer 197/71X 3,086,635 4/1963 Palmer 197/16 3,157,265 11/1964 Palmer 197/16 3,191,740 6/1965 Smusz et al... 197/16 3,228,511 l/1966 Meinherz 197/74 3,295,653 1/1967 Salto 197/107X 3,311,211 3/1967 Schaefer 197/98 3,348,648 10/1967 Frechette 197/16 3,353,646 11/1967 Young 197/16 3,386,554 6/1968 Everhard 197/71 Primary ExaminerErnest T. Wright, Jr. Attorneys-Joseph R. Spalla and Cornelius P. Quinn ABSTRACT: A typewriter provided with a bail operatively v PATEN'TEUHAR 91971 3,568,811

' sum 1 or 4 ATTOR N EY PATENTEDH'AR elsn 3568.811

' sum 2 or 4 INVENTOR ARTHUR R. JOHNSON ATTORNEY TPATENTEBHAR-QIQYI 3.568.811

' sumanm INVENTOR ARTHUR R. JOHNSON ATTORNEY PATENTEDM'AR 9 1971 sum u 0F 4 INVENTOR ARTHUR R. JOHNSON BY fw ATTORNEY MEMORY SYSTEM F OR AN ELECTRIC TYPEWRITER BACKGROUND OF THE INVENTION This invention relates to a memory systems for an electric typewriter having a cam-driven type action and more particularly to a memory system characterized by interposer means responsive to a type action or shift action to block any subsequently initiated action until preceding type action or shift action has been substantially completed.

The end product of any typewriter is the copy it produces. Accordingly, it is highly desirable for a typewriter to be capable of producing copy of high definition, uniform density, and proper letter spacing at a high rate of speed. Inasmuch as the keyboard is the primary control of the entire machine, i.e. the input portion thereof, it should function in response to a typiss manipulations with a degree of precision and celerity and at the same time be so arranged as to preclude. any possiblity of jamming, overstriking, blurring and any other factor that adversely affect the quality of the copy as a result of improper or inadvertent operation.

Normally in an electric typewriter, a time interval of 60 -80 milliseconds elapses'between the initiation of a type bar movement and itsreturn to a headrest. This time interval represents a typing rate; its return to a headrest. This time interval represents a typing rate faster than that which can be sustained by a skilled typist and accordingly allows a skilled typist to type at am rapid rate of speed. However, it is sufficiently long as to make it possible for a typist to roll off two characters of some character combinations in quick succession initiating movement of a first type bar and then initiating movement of a second type bar before the first type bar has returned to the headrest. In such instances, quite often the type bars will clash or causecrowding of characters on the writing line adversely affecting the quality of the copy produced.

Still another problem in such mechanisms is the occurence of flying caps, which result when a typist quickly depresses a character key and a shift key in close succession or vice versa and a character strikes the platen while the typewriter segment is being shifted SUMMARY The present invention provides an electric typewriter having a cam type cation with interposer means operatively positioned upon initiating of a first type action to block the drive of asubsequently initiated type action or shift action and hold it in memory until the first type action has been substantially completed. The same interposer means is also operatively positioned upon initiation of a shift action to block the drive of any subsequently initiated type action and hold it in memory until the shift action has been substantially completed.

An object of the present invention is to provide means in an electric typewriter preventing the occurence of the clashing of type bars and the crowding of characters on the same writing line.

Another object of the present invention is to provide means in an electric typewriter preventingthe occurrence flying caps.

A further object of the present invention is to provide a memory system for an electric typewriter in which any type action initiated subsequent to the initiation of a first type action or a shift action is blocked and held in memory until the first type action or the shift action has been substantially completed.

Still another object of the present invention is to provide a memory system for an electric typewriter in which any type or shift action initiated subsequent to the initiation of a first type action is blocked and held in memory until the first type action has been substantially completed.

Other objects and, advantages of the present invention will become apparent tothose skilled in the art from a consideration of the followingdescription read in conjunction with the drawing.

IN THE DRAWING FIG. 1 is a perspective view of a portion of an electric typewriter embodying the memory system of the present invention FIG. 2 is an enlarged fragmentary view of a rockable cam associated with a second type action striking a flexible finger formed on an operative interposer bail;

FIG. 3 is a perspective view of the portion of the embodiment of the invention illustrated in FIG. 1, with the rockable cam associated with the second type action held in sliding frictional engagement with a power roll;

FIG. 4 is an enlarged fragmentary view of the illustration in FIG. 3 showing the rockable cam being held in sliding frictional engagement with the power roll;

FIG. 5 is a side elevational view of a portion of the mechanism illustrated in FIG. 1 showing the release from memory of a rockable cam;

FIG. 6 is a perspective view of a portion of an electric typewriter illustrating the present invention cooperatively associated with an electric typewriter shift mechanism;

FIG. 7 is a front elevation view of a portion of the shift mechanism illustrated in FIG. 6; and

FIG. 8 is a side perspective view of a cam face of the shift mechanism illustrated in FIGS. 6 and 7.

PREFERRED EMBODIMENT OF THE INVENTION The memory system of the present invention is particularly directed to electric typewriters employing cam-driven type actions. Referring now to the drawing wherein like reference characters designate like or corresponding parts throughout the several views, there is illustrated in FIG. 1 a key-controlled linkage generally designated by the reference numeral 28 having a key lever 29 which is fulcrumed on a cross-shaft 30 secured to the machine frame and depressed to effect the initiation of a type action. Upper and lower limits of the travel of the key lever 29 are determined by a pair of shoulders 31 and 32 formed in the key lever 29 engaging a stationary stop 27. The key lever 29 has a depending finger 33 which engages the upper surface of a bent off. shelf 34 formed on the forward end of a rigid or nonflexible intermediate control lever 35 that is pivotally mounted on a cross-shaft 36 secured to the machine frame. An angularly extending reward portion of lever 35 terminates with a tip 37 that normally underlies the lower edge of a tail 38 formed on a rockable cam or cam member 21.

The rockable cam 21 is pivotally mounted on a sublever 15 of an actuating linkage generally designated by reference numeral 14, pivotally mounted on a shaft 16 secured to the frame. As best seen in FIG. 5, the engagement of a bent off ear 23 on the rockable cam 21 with an adjacent edge 24 of the sublever 15 determines the counterclockwise limit of movement of the rockable cam 21. A type bar 10 pivotally mounted on a segment wire 11, is connected by a link 20 to the sublever 15. The actuating linkage 14 is adapted to drive the type bar 10 from a normal position on a headrest 12 into printing contact with a a typewriter platen 13.

In operation, the cam 21 is to be displaced in a clockwise direction so as to move into operative frictional driving engagement with a constantly rotating power roll 25, thereby initiating drive to the type bar 10, and upon striking an adjustable impression control stop 121 (FIG. 3), becomes disengaged from the power roll 25 and returns counterclockwise to a rest position under the action of spring 22. After typing impact, a return spring 26 returns the type bar 10 and sublever 15 to their normal position.

For brevity, the corresponding parts of a second type action identical with the one described above are identified by the same numerals noted above with the addition of a subscript a.

The sublevers 15 and 15: each have a forwardly extending tail, 40 and 40a respectively, adapted to overlie a U-bar Ill pivotally mounted on the frame.

Again with particular reference to FIG. 1, a cam interposer bail 42 is slidably mounted for movement forwardly and rearwardly relative to horizontally spaced frame supported pins 44 projecting upward through angular slots 43 formed in the cam interposer bail 42. Normally the bail 42 is biased to a rearward position by two springs 45 secured thereto at either end and to the frame. A rigid link 46 articulately connects the right end of cam interposer bail 42 to a lever 47, pivotally mounted on a vertical frame supported pivot 47a and adapted when powerrocked clockwise as viewed in FIG. 1, to move the cam interoser bail 42 forward as will hereinafter appear, in response to counterclockwise movement of U-bar 41.

A power assist mechanism generally designated by the reference numeral 53, comprises two arms 48 and 49 rotatably mounted on a shaft 51 extending from the right end of the power roll 25 as viewed in FIG. 1 and connected to opposite ends of a wrap spring 50 telescoping the shaft 51. The wrap spring 50 is wrapped counterclockwise from right to left as viewed in FIG. 1 and is adapted to momentarily wrap about the shaft 51, i.e. only during counterclockwise movement of arm 49, driving the arm 48 counterclockwise, and, when the forward motion of the arm 49 ceases, to unwrap. In response to clockwise or rearward movement of the arm 49, the wrap spring 50 rotates clockwise about shaft 51 moving the arm 48 to the rear. Arm 48 is adapted to engage and move lever 47 counterclockwise in response to counterclockwise movement of arm 49 which is articulately connected to the end of the U- bar 41 by a rigid link 52.

In operation, when a first alpha-numeric key such as the alpha-numeric key lever 29 is depressed for example, the intermediate control lever rocks the cam 21 into driving engagement with the power roll 25. As the cam 21 is driven clockwise by the power roll 25, it rocks the sublevel counterclockwise causing the tail 40 to pivot U-bar 41 counterclockwise, and thereby rotates lever 49 counterclockwise. The counterclockwise rotation of level 49 causes wrap spring 50 to wrap about the shaft 51 driving arm 48 counterclockwise, which pivots the lever 47 clockwise about its pivot 47a and thereby moves the cam interposer bail 42 against the bias of the interposer bail springs 45 to a forward position directly in the path of cam 21 a With the interposer bail 42 in a forward position, the path of the cam 21 of any subsequently depressed alpha-numeric key will be blocked and held from delivering a printing stroke to a type bar 10 until the interposer bail 42 moves to the era. For example, if lever 29a is depressed while the action initiated by lever 29 is in progress, the cam 21a will strike a flexible finger 60 depending from an upward extension of the cam member interposer bail 42 into the path of cam 21 a as illustrated in FIG. 2 and then abut the forwardly positioned interposer bail 42 as illustrated in FIGS. 3 and 4.

As illustrated in FIG. 4, the path of the cam 21a is not only blocked by the interposer bail 42, but the interposer bail 42, but intercepts the cam 21a at a point at which the lower portion of the cam 21a is in slipping engagement with the power roll 25. The cam 21a is of such a configuration that the frictional force between the power roll 25 and the cam 21a while the cam 21a is held by the interposer bail 42, is sufficiently small to allow the cam 21a to slip without abrading the surface of the cam 21a or the power roll 25, and at the same time is sufficiently large to overcome the force of the spring 22a urging the cam 21a counterclockwise, so that when the interposer bail 42 is retracted from the path of cam 2la,the power roll 25 will continue to drive the cam 21a and the type bar 10a through a power stroke.

The purpose of the flexible finger 60 overhanging the top of the cam 21a is to capture and to prevent the cam 21a from bouncing off the power roll 25 and returning upward to its rest or normal position under the urge of spring 220 while the interposer bail 42 is in a forward position.

The purpose of the flexible finger 60 overhanging the top of the cam 21:: is to capture and to prevent the cam 21a from bouncing off the power roll 25 and returning upward to its rest or normal position under the urge of spring 220, while the interposer bail 42 is in a forward position.

After the type bar 10 strikes the platen 13, the sublever 15 releases the U-bar 41 allowing the U-bar 41 to follow the tail 40 to a normal position under the action of a spring 61 connected to the U-bar 41. This movement of the U-bar 41 pivots lever 49 clockwise rotating spring 50 about shaft 51 and lever 48 clockwise out of the path of lever 47, whereby the springs 45 take over and move the interposer bail 42 back out of the path of the cam 21a as illustrated in FIG. 5.

With the interposer bail 42 removed from the path of cam 21a, the frictional contact of the power roll 25 with the cam 21a is sufficient to reestablish driving movement of the cam 21a to drive the type bar 10a into contact with the platen 13.

Accordingly, even though a type bar 10 associated with a first depressed alpha-numeric key, such as the type bar 10 associated with the cam 21, may be only 20 to 30 off the headrest 12, and a type bar collision would normally be expected if a second alpha-numeric key were depressed, such as 29a, a collision is avoided by the interposer bail 42 delaying the drive to the type bar 10a associated with the second alphanumeric key 29a until the type bar 10 associated with the first alpha-numeric key 29 strikes the platen 13 and has returned to a position at or substantially close to its headrest 12.

With particular reference to FIG. 6, for reasons which will hereinafter appear, the left end of the interposer bail 42 is articulately connected by a rigid link 91 to an interposer lever 63, pivotally mounted on a vertical frame supported pin 63a and adapted to delay a shift action initiated in response to movement of a shift key lever 75 pivotally mounted on the frame, while the interposer bail 42 is in the blocking position illustrated in FIG. 3 due to a type action in progress.

More particularly, as illustrated in FIGS. 6 and 7, there is shown a shift mechanism comprising a wrap spring 64 telescoped about a shaft 65 extending from the left end of the power roll 25, as viewed in FIG. 6. The wrap spring 64 is connected at one end to a shift eccentric generally designated by the reference numeral 66 rotatably mounted inwardly of the free end of shaft 65. A shift eccentric follower 66' via spaced crank arms 67, 67 interconnected by a shaft 67 is operable to move a type-bar segment member generally designated between a normal position in which a lower portion of a type formed on the type bars 10 is adapted to strike the platen 13 and a lower position in which an upper portion of the type formed on the type bars 10 is adapted to strike the platen 13. The other end of the wrap spring 64 is connected to a shift trip star wheel 68 coaxially mounted on the shaft 65, and having two teeth 69 and 70 formed 180 apart. A pair of lugs 71 and 72 posteriorly positioned relative to teeth 69 and 70 respectively, protrude from the side of the shift trip star wheel 68. The lug 71 is positioned adjacent to the periphery of the shift trip star wheel 68 and is adapted to be engaged by a bent out ear 76 of the shift key lever 75 when the shift key lever 75 is in a normal position. The lug 72 is radially offset a greater distance from the periphery of the shift trip star wheel 68 than the lug 71 and is adapted to be engaged by the bent out ear 76 of the shift key lever 75 when the shift key lever 75 is in a depressed position.

As illustrated in FIG. 8, the shift eccentric 66 has a cam face 77 with an annular profile including two dwells 78 and 79 spaced equidistances apart. A depending profile follower arm 82 forming part of the interposer lever 63 is biased by the interposer bail springs 45 into contact with the profile of cam face 77. A second depending arm 83 forming part of lever 63 is adapted to move into the path of the teeth 69 and 70 when the interposer lever 63 is in a clockwise position, and out of the path of the teeth 69 and 70 when the interposer lever 63 is in a counterclockwise position.

In operation, when the shift key lever 75 is depressed removing the bent out ear 76 from the path of lug 71 and into the path of lug 72, the wrap spring 64 is allowed to wrap about the shaft 65, coupling the shaft 65 and rotating the shift eccentric 66 one-half revolution counterclockwise thereby moving the typewriter segment member S to its lower position, and rotating the shift trip star wheel 68 until the lug 72 abuts the ear 76. It is to be noted here that following engagement of the shift cycle clutch, the lug 69 or 70 as the case may be, will have rotated sufficiently before the cam profile driven lever 63 has rotated to the degree as would move arm 83 into the path of lug 69 or 70. During the travel of the shift eccentric 66, the depending profile follower arm 82 guided by the annular profile of the cam face 77, moves the interposer lever 63 to a clockwise position pulling via rigid link 91 the interposer bail 42 forward and into the path of the cams 21 and 21a associated with the alpha-numeric keys 2 9 and 29a. When the shift eccentric 66 completes its 180 travel, and the depending profile follower arm 82 reaches the dwell 79, the interposer bail springs 45 move the interposer bail 42 back out of the path of the cams 21 and 21a. This movement of the interposer bail 42 is transmitted to the interposer lever 63 by the link 91 and pivots the interposer lever 63 counterclockwise.

Similarly, when the shift key 75 is released disengaging ear 76 from the lug 72, the wrap spring 64 engages the shaft 65 driving the shift eccentric 66 another half-revolution moving the typewriter segment member S to a normal position. During this 180 travel of the shift eccentric 66 and movement of the typewriter segment to a normal position, the profile follower arm 82 holds the interposer lever 63 in a clockwise position pulling the interposer bail 42 forward and into the path of the cams 21 and 21a. When the shift eccentric 66 completes its 180 travel and the profile follower arm 82 reaches the dwell 78, the springs 45 move the interposer bail 42 back out of the paths of cams 21 and 21a.

Since the interposer lever 63 and the interposer bail 42 are articulately connected by link 91, whenever the interposer bail 42 is moved forward as the result of an alpha-numeric key 29 being depressed, the link 91 moves the interposer lever 63 to a clockwise position placing the depending arm 83 into the path of teeth 69 and 70. With the interposer lever 63 in a clockwise position, should a shift action be initiated in response to the depression or release of the shift key lever 75, moving car 76 from the path of lug 71 or 72, as the case may be, the depending arm 83 will almost immediately engage either tooth 69 or 70, thus delaying shift movement until the type action resulting from the depression of the alpha-numeric key 29 has been substantially completed and the interposer bail 42 and interposer lever 63 return to their normal inoperative position.

The return of the interposer lever 63 to a counterclockwise position, moves the depending arm 83 out of the path of teeth 69 and 70, releasing the shift trip star wheel 68, whereby the wrap spring 64 couples the shaft 65 driving the shift eccentric 66 until it completes a shift of the typewriter segment member S that was called during the type action.

Thus, the memory system mechanism described above accomplishes all the objects of the present invention by delaying drive of a second action until after the first-initiated type or shift action has been substantially completed.

it should be understood that the foregoing disclosure relates to only a preferred embodiment of the invention and that the claims are intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

1. In an electric typewriter having a power roll, a plurality of type-bar-actuating linkages each including an eccentric cam member mounted for movement into engagement with said power roll thereby to cause its associated linkage to accomplish a printing stroke,

a plurality of control linkages for moving said cam members into engagement with said power roll, bail means movable from an inactive position out of the path of movement of said cam members to an active cam arresting and holding position, at which a cam member is held in nondriving contact with said power roll,

a universal bar pivotally supported in contact with and to follow the movement of said type bar actuating linkages,

and means response to the movement of said universal bar to move said bail means to active position to arrest and hold a cam member moved toward power roll engagement during the printing stroke of type-bar-actuating linkage driven by a first engages cam member.

2. A typewriter as recited in claim 1 wherein said bail means includes a bail slidably mounted on the frame of the typewriter for movement into the path of and to arrest movement of a cam member in response to movement of a previously driven type-bar-actuating linkage, said bail including a flexible finger formed on and overhanging forwardly of the bail to hold a cam member from bouncing off said power roll and from returning to a normal position during a previously initiated printing stroke.

3. In an electric typewriter having a power roll, a plurality of type bars and a type-bar-segment member movable from one to another case position,

type-bar-actuating linkages each mounting an eccentric cam member for movement into engagement with said power roll thereby to drive said type bar actuating linkages,

a shift cycle clutch,

means including a shift eccentric operable when clutched to said power roll by said shift cycle clutch to move said segment member,

shift key controlled linkage for effecting engagement of said shift cycle clutch,

bail means biased to and movable from an inactive to an active cam member arresting and holding position, and

and means response to shift eccentric operation for moving said bail means to active position thereby to arrest and to hold a cam member moved toward engagement with said power roll in nondriving engagement with the power roll over the interval of operation of the shift eccentric.

4. A typewriter as recited in claim 3 wherein said means responsive to shift eccentric operation for moving said ball means to active position comprises a cam profile on the face of said shift eccentric and a cam profile follower linked to move said bail means.

5. In an electric typewriter having a power roll, a plurality of type-bar-actuating linkages each including an eccentric cam member mounted for movement into engagement with said power roll thereby to cause its associated type bar actuating linkage to accomplish a printing stroke,

a plurality of control means for moving an associated one of said cam members into power roll engagement,

a type-bar segment member shiftable from one to another case position,

a shift cycle clutch,

a shift cam operable when clutched to said power roll by said shift cycle clutch to shift said segment member from one to the other case position,

a shift linkage for effecting engagement of said shift cycle clutch,

a universal bar pivotally supported in contact with and to follow the movement of driven type-bar actuating linkages,

bail means biased to and movable from an inactive position out of the path of a cam member to an active cam member arresting position during a shift clutch cycle or during a printing stroke, thereby to arrest a cam member moved toward power roll engagement during movement either of said shift cam or during a printing stroke driven by a first engaged cam member,

means responsive to movement of said universal bar for moving said bail means to active position,

means responsive to said shift cam movement for moving said bail means to active position,

and means associated with id shift cycle clutch and responsive to movement of said bail means to active position to delay shift cycle clutch engagement while said bail means is in active position. 

2. A typewriter as recited in claim 1 wherein said bail means includes a bail slidably mounted on the frame of the typewriter for movement into the path of and to arrest movement of a cam member in response to movement of a previously driven type-bar-actuating linkage, said bail including a flexible finger formed on and overhanging forwardly of the bail to hold a cam member from bouncing off said power roll and from returning to a normal position during a previously initiated printing stroke.
 3. In an electric typewriter having a power roll, a plurality of type bars and a type-bar segment member movable from one to another case position, type-bar-actuating linkages each mounting an eccentric cam member for movement into engagement with said power roll thereby to drive said type bar actuating linkages, a shift cycle clutch, means including a shift eccentric operable when clutched to said power roll by said shift cycle clutch to move said segment member, shift key controlled linkage for effecting engagement of said shift cycle clutch, bail means biased to and movable from an inactive to an active cam member arresting and holding position, and and means response to shiFt eccentric operation for moving said bail means to active position thereby to arrest and to hold a cam member moved toward engagement with said power roll in nondriving engagement with the power roll over the interval of operation of the shift eccentric.
 4. A typewriter as recited in claim 3 wherein said means responsive to shift eccentric operation for moving said bail means to active position comprises a cam profile on the face of said shift eccentric and a cam profile follower linked to move said bail means.
 5. In an electric typewriter having a power roll, a plurality of type-bar-actuating linkages each including an eccentric cam member mounted for movement into engagement with said power roll thereby to cause its associated type bar actuating linkage to accomplish a printing stroke, a plurality of control means for moving an associated one of said cam members into power roll engagement, a type-bar segment member shiftable from one to another case position, a shift cycle clutch, a shift cam operable when clutched to said power roll by said shift cycle clutch to shift said segment member from one to the other case position, a shift linkage for effecting engagement of said shift cycle clutch, a universal bar pivotally supported in contact with and to follow the movement of driven type-bar actuating linkages, bail means biased to and movable from an inactive position out of the path of a cam member to an active cam member arresting position during a shift clutch cycle or during a printing stroke, thereby to arrest a cam member moved toward power roll engagement during movement either of said shift cam or during a printing stroke driven by a first engaged cam member, means responsive to movement of said universal bar for moving said bail means to active position, means responsive to said shift cam movement for moving said bail means to active position, and means associated with id shift cycle clutch and responsive to movement of said bail means to active position to delay shift cycle clutch engagement while said bail means is in active position. 